Cigarette filter feed

ABSTRACT

Cigarette filters of two lengths are fed as an ordered stream to a filter applying machine. The feed is formed by subjecting a scrambled or jumbled mass of the filters to centrifugal forces in a shallow bowl, the filters thereby forming a stream around the inner periphery of the bowl, and removing filters from the stream.

United States Patent 11 1 Brackmann et a1.

[ CIGARETTE FILTER FEED [75] inventors: Warren A. Brackmann, Cooksville;

Daniel DiIanni, Toronto, both of Canada [73] Assignee: Rothmans of Pall Mall Canada Limited, Toronto, Ontario, Canada [22] Filed: Nov. 23, 1971 [21] Appl. No.: 201,411

52 us. c1. 198/33 R, 221/160 51 1111. c1. ..-B65g 47/24 53 Field of Search 221/171, 157,158,

[56] References Cited UNITED STATES PATENTS 2,523,517 9/1950 Potter 198/30 X 1451 July 3,1973

3,168,949 2/1965 Aidlin 198/30 2,665,005 I 1/1954 Mundy... 221/159 x 3,500,981 3/1970 Yann 198/30 3,212,668 10/1965 Gleason et al. 221/157 X FOREIGN PATENTS OR APPLICATIONS 1,558,060 2/1969 France 198/30 Primary Examiner-Richard E. Aegerter Assistant ExaminerH', S. Lane AnorneyPeter W. McBurney et al.

[57] ABSTRACT Cigarette filters of two lengths are fed as an ordered stream to a filter applying machine. The feed is formed by subjecting a scrambled orjumbled mass of the filters to centrifugal forces in a shallow bowl, the filters thereby forming a stream around the inner periphery of the bowl, and removing filters from the stream.

5 5 Claims, 8 Drawing Figures PATENIEDJUI. 3 I975 3.743.075 .SIEEI 1 0F 2 22 1 2 "1 G 2o 1O FILTER 14 FILTER 18 FILTER MAKING FEED FoRMING APPLYING MACHINE APPARATUS MACHINE FIG. 1 Q 24 FILTER MAKING MACHINES f L a FIG 2 FILTER L I O} AccuMuLAToR FILTER APF L YING MACHINES 38 PAIENIEnJuw ms SHEEI 2 BF 2 FIG. 7

CIGARETTE FILTER FEED This invention relates to the manufacture of cigarettes, more particularly to the provision of a feed of cigarette filters.

In the manufacture of cigarettes, a continuous cigarette rod first is formed, discrete cigarette lengths are cut from the rod, and filters are attached to the cigarette lengths. Generally, filters having twice the normal filter length are attached between two cigarette lengths and the filter subsequently is cut substantially at the mid-point of its length, giving two cigarettes each having the required filter length.

The commonly employed two-length filters are formed in two stages. First, a continuous length of filter material is formed which is cut into relatively long lengths, usually equivalent to about six filter lengths. The relatively long lengths are cut in a second step to form the two length filters. It is necessary to employ this two stage operation in view of handling problems associated with the two-length filters, as discussed further below.

Additionally, certain cigarette filters of a specialized type, such as filters including a plurality of filter elements, can only be made readily in one or two length forms and hitherto there has not been found a satisfactory method of feeding such elements to the commonly employed filter applying apparatus.

In the conventional filter-applying operation, filter material, after cutting into lengths from the continuous rod must be transported to the filter applying apparatus. In order to achieve a commercially satisfactory rate of manufacture of finished cigarettes, the feed to the filter applying apparatus must be a regular flow of individual filters, so that continuity of application of filters to the cigarettes is ensured.

It has been found that it is not possible to stack single or two-length filters regularly at the desired rate of formation of such filters, but rather such filters form a jumbled mass which is not acceptable by the filter applying machine. Hence the two-length filters are not suitable, in the prior art system, for feed to a filter applying apparatus. The relatively long lengths, however, may be stacked regularly. Therefore, these relatively long lengths are cut from the continuous rod and stacked in suitable trays, usually having side walls spaced apart the length of such relatively long lengths. The filters are stacked between the side walls with their longitudinal axes parallel. The trays containing such filters are transported from the filter making machine to the filter apply machine, and the tray feeds the filters to the filter applying machine. In this machine, it is necessary that the relatively long lengths be cut to form a plurality of two-length filters. These latter filters are readily handled within the apparatus for feed to the cigarette tipping operation therein.

Generally, a single filter making machine producing relatively long lengths, such as six-length, of filter material feeds a plurality of filter applying machines. With the specialized filters mentioned above which are made only in single or two-length forms, no satisfactory feed mechanism has been devised to achieve a commercially acceptable level of manufacture of finished cigarettes including such filters.

The present invention seeks to greatly simplify the above operation by allowing single or multiple length filters either cut from a continuous rod or formed in any other manner to be fed to the filter applying machines at a commercially aceptable rate and modifications to the machines to accept a single or multiple length filter feed.

The present invention provides a method of providing a filter feed of singleor multiple-length filters to a filter-applying apparatus in which a jumbled or scrambled mass of filters is received at the filter applying apparatus and in which the filters are unscrambled and aligned at high speeds to provide an ordered feed for the filter applying apparatus.

The present invention also provides apparatus which provides an ordered flow of cigarette filters of single or multiple (usually two) length from a scrambled or jumbled mass of such filters.

Additionally, in accordance with the present invention, a unique system of cigarette filter distribution is provided in which single or multiple-length filters are formed at a plurality of stations, the filters formed at each station are forwarded to an accumulator, and filters are distributed as a scrambled mass as required from the accumulator to a plurality of filter applying stations.

The invention will be described hereinafter with particular reference to two-length filters since most commercially utilized filter applying machines employ such filters, but it is understood that the invention also is applicable to single and other multiple length filters.

In the present invention, the filter applying apparatus is modified by the use of a shallow circular bowl which is mounted for rotation about a substantially vertical axis. The two-length filter elements are fed as a scrambled or jumbled mass to the bowl, which is rotated to cause the two-length filter elments to be subjected to centrifugal forces. The effect of the centrifugal forces when applied at a sufficiently high level is to form a stream of filters around the inner periphery of the bowl. The filters in the stream are end-to-end aligned and generally in engagement with each other. The stream is removed from the bowl, usually as a substantially continuous stream of filters.

The present invention is illustrated by the accompanying drawings, in which:

FIG. 1 is a schematic representation of the feeding of filters in accordance with the present invention;

FIG. 2 is a schematic representation of the distribution system of the invention;

FIG. 3 is a schematic representation of part of a filter applying machine modified in accordance with the present invention;

FIG. 4 is a view taken on line 4-4 of FIG. 3;

FIG. 5 is a plan view of a filter feeding apparatus in accordance with the present invention;

FIG. 6 is a sectional view taken along line 66 of FIG. 5;

FIG. 7 is a detail close-up of the periphery of the bowl shown in FIGS. 5 and 6; and

FIG. 8 is a detail of the apparatus to remove filters from the bowl shown in FIGS. 5 and 6.

Referring to the drawings, in FIG. I, cigarette filter material is fed by line 10 to a filter making machine 12 in which the filter material is formed into a continuous rod and the rod is formed into individual filter lengths in known manner. As mentioned above, it is usual for the continuous rod to be cut into relatively long lengths. However, in the present invention, single'or double length filters usually are provided. This generally is achieved by forming the relatively long lengths in the usual way and then cutting these lengths into single or multiple lengths. The equipment presently used in filter applying machines may be utilized to cut the relatively long filter lengths.

Alternatively, the filter making machine 12 may be of a form used to make speciality filters containing-multiple filter elements of single or two-length.

The filters formed in the filter making machine is fed by line 14 as a scrambled mass to a filter feed forming apparatus 16. In the filter feed forming apparatus, the mass of filters is unscrambled to form at high speed an ordered stream of filters which is fed by line 18 to the filter applying machine 20.

In practice, the filter forming apparatus 16 is located physically adjacent the filter applying machine 20, as indicated below with reference to FIG. 3. For the convenience of illustrating the operations involved in the present invention, the filter applying apparatus 16 is shown physically separate from the filter applying machine 20.

The filter applying machine 20 may be of conventional form except that the operations of cutting and separating relatively long length filters are omitted. Cigarette rods are fed by line 22 to the filter applying machine 20 and in conventional manner a two-length filter fed by line 18 is placed between and secured to two adjacent cigarette rods, and the filter subsequently is cut in the middle to provide two filter-tipped cigarettes. The filter-tipped cigarettes pass from the filter applying machine 20 by line 24 to packaging operations.

FIG. 1 illustrates a simplified operation in which all of the filters formed in one machine 12 are passed to one filter applying machine 20. Generally, however, the filter making machine 12 produces filters at a much faster rate than the applying machine 20 is able to utilize them. Therefore, in practice, one filter making machine 12, producing approximately 2,000 6-length or about 6,000 two-length filters a minute feeds a plurality of filter applying machines 20, such as operating at about 750 double length cigarettes per minute.

Further the arrangement of FIG. 1, in many cases, may be impractical, since a factory generally has a plurality of filter making machines 12 and a plurality of filter applying machines 20 which are physically located some distance from each other.

The schematic arrangement shown in FIG. 2 illustrates a practical scheme for distribution of filters. The schematic arrangement 30 includes a plurality of filter making machines 32, five of which are shown but any number of which may be employed, depending on the output desired, and other factors. Each of the filter making machines 32 forms two-length filters.

The filter output from each of the filter making machines 32 is fed by lines 34 to a filter accumulator 36. Thus, a jumbled mass of two-length filters is provided in the filter accumulator.

A plurality of filter applying machines 38 is provided for feed by lines 40 from the filter accumulator 36. While the number of filter applying machines 38 is illustrated to be the same as the number of filter making machines 32, the relative numbers may be varied, depending on the relative rates of operation of the filter making machines 32 and the filter applying machines 38. Generally, there are more filter applying machines 38 than filter making machines 32.

Therefore, a scrambled or jumbled mass of filters is fed from the accumulator 36 to each of the filter applying machines 38 as required. The jumbled mass is sorted at high speed into an ordered stream of filter elements at each of the filter applying machines, as indicated in FIG. 1.

In the scheme of FIG. 2, therefore, filter elements are formd at a plurality of filter making stations, the elements so formed all are passed to a central filter element storage area, or accumulator, and a scrambled mass of filter elements is fed from the storage area to each of a plurality of filter applying stations. This scheme is in contrast to the presently practised arrangement in which a single filter making machine forms relatively long length filter elements and these elements are passed to a plurality of separate filter applying machines as an ordered mass.

In the scheme of FIG. 2, a filter element formed on one of the machines 32 may be fed to any of the machines to 5 of type 38. Further, filter elements in the scrambled mass fed to any one of the machines 1 to 5 of the type 38 may have originated from any one of the filter making machines 32.

25 While there is illustrated in FIG. 2 a scheme including a single accumulator 36, in a factory there may be a plurality of accumulators of the type 36, depending on the desired output, of each of the accumulators being fed by a plurality of filter making machines 32 and feeding a plurality of filter applying machines 38.

Each of the filter applying machines 38 may be in the form shown schematically in FIGS. 3 and 4. A jumbled mass of cigarette filters 100 is contained in a hopper 102 for feed to an unscrambling device 104, which is described in more detail below with reference to FIGS. 5 and 8. The unscrambling device forms from the mass of filters 100 a stream of end-to-end aligned filters 106 in a feed tube 108, in a manner described below. The filters in the stream 106 usually are in touching relationship but such an arrangement is not essential.

The filter elements in the stream 106 are fed between a pair of opposed continuous conveyor belts 110. The belts 110 move in the same direction and the opposed faces are resiliently mounted relative to each other to grip the elements therebetween and transport them from the tube 108 to engage a surface of a rotating wheel 112. The filters are prevented from passing beyond the wheel 112 by a stop 114. When the leading filter element is arrested by the stop 114, the filters between the conveyor belts 110 similarly are stopped. However, the conveyor belts 110 continue to operate and slip over the external surface of the filters held therebetween.

The wheel 112 includes a series of radial projections 116 circumferentially spaced from each other. The wheel 112 rotates and as a projection 116 on the periphery of the wheel engages the leading filter element, a component of lateral motion is imparted thereto and the element is removed from the feed stream. As the lead filter becomes disengaged from the next-in-line filter, the latter filter is projected by the operation of the conveyors 110 against the stop 114 to be engaged by the next projection 116. The speed of rotation of the wheel 112 and the spacing of the projections is such that one filter is received between each adjacent pair of circumferentially spaced projections. The projections 1 16 extend axially the thickness of the wheel 112.

In this way, filters in the stream 106 are arranged in the form of a plurality of individual filters 117 laterally aligned with respect to the peripheral surface of the wheel 112 and circumferentially spaced from each other.

The filters are transported in engagement with the peripheral surface with the aid of camming surface 118 to a position diametrically opposed to the feed position.

A rotating drum 120 has a plurality of axially aligned flutes 122 about the periphery thereof. To each of the flutes 122 is fed by means, not shown, in conventional manner, two cigarette rods 124 which are spaced from each other in the flutes 122 a distance approximately the length of a two-length filter element.

The filter 117 transported by the wheel 112 to the position diametrically opposed to the feed position is positioned between the two cigarette rods 124 on the flute 122. The filter elements 117 then are affixed to the cigarette rods 124 in conventional manner, by wrapping with and adhering to cork paper.

A double length cigarette thus is formed which then is sliced in the middle of the filter in conventional manner to provide two cigarettes, which then are passed from the machine to a packaging station. a

The arrangement described above with reference to FIGS. 3 and 4 represents only one way in which the filter feed provided by the unscrambling device 104 which may be used to form filter-tipped cigarettes. Alternative arrangements and modifications of the abovedescribed arrangement clearly are possible.

Unscrambling device 104 described in relation to FIGS. 3 and 4 is now more particularly described with reference to FIGS. 5 to 8. The unscrambling device or feed apparatus 104 includes a disc or shallow bowl 126 of circular cross-section having a side wall 128 and a flat bottom closure 130. The wall 128 of right cylindrical shape and the bottom closure 130 is located in a plane substantially transverse to the axis of the cylinder. The bowl 126 is mounted for driving rotation on a substantially vertical spindle 132 which is driven by an electric motor (not shown). The vertical spindle 132 is journalled for rotation in a stationary bearing 134 which is connected to part of the frame (not shown) of the filter applying machine shown in FIGS. 3 and 4.

The bowl 126 is mounted substantially horizontally and any other suitable driving and mounting means may be adopted.

The bowl 126 may be of any convenient diameter and depth depending on a number of variable factors, such as rate of feed of filters required.

The bottom closure 130 has a groove 136 of part circular cross section formed adjacent the wall 128. It may be desired to apply a' vacuum over an arcuate length of the groove 136 and this may be achieved by providing a plurality of openings wich pass axially of the bowl 126 from the groove 136 to the bottom surface of the closure 130. A suction pipe may be provided, communicating with a stationary arcuate inverted channel which is positioned over an arcuate length of the openings. In this way, vacuum may be applied to the openings over a limited arcuate length of the groove 136.

An annular cover 138 is provided parallel with and spaced from the bottom closure 130. The cover 138 is mounted to the stationary bearing 134 by arms 140. The cover 138 is positioned adjacent the periphery of the bowl 126. The outer periphery of the cover 138 is curved downwardly at 142 towards the groove 136. The function of this curved periphery is described in detail below.

The annular cover 138 defines with the bowl 126 an opening 144 to allow a jumbled mass of filter elements to be fed from the hopper 102 to the bowl 126.

Generally, the distance between the cover 138 and the bottom closure is about the diametric size of the filter elements, so that a single layer of filters is present in the peripheral area of the bowl 126.

An elongated tube 146 (FIG. 8) serves as a feed pipe for the remainder of the filter applying apparatus of FIG. 3 and communicates with the pipe 108 and is mounted on a bracket 145 affixed to the cover 138.

The tube 146 projects into the bowl 126 at an inclined angle, acute in the intended direction of movement of the bowl 126, and terminates in a finger 149 which projects into the groove 136 and engages the bottom of the groove. The tube 146 also includes a mouth which is shaped so that it isopen to the front and towards the wall 128 but is closed towards the interior of the bowl.

In operation, twolength filter elements, or other light cylindrical elements, are fed to the bowl 126 by the hopper 102 through the opening 144. The hopper 102 containing a supply of elements 100 as a jumbled mass may feed quantities thereof continuously or intermittently as desired to the bowl 126. The bowl 126 may include a sensing device to determine when the quantity of the elements falls below a desired level, the sensing device being coordinated with the hopper 102 to feed the elements when the level of elements drops below that desired.

Upon rotation of the bowl 126 in a clockwise direction, as seen in FIG. 5, by the action of the spindle 132, the elements in the bowl 126 under the centrifugal action are displaced towards the wall 128 and form in the groove 136, and hence in a substantially horizontal plane, a stream of filter'elements. If there are more filter elements in the bowl 126 than there is space available in the groove for elements, then the stream is substantially continuous, and the elements in such stream are in end-to-end touching relationship. Any filter elements in the bowl and not forming the stream attempt to position themselves as far as possible from the centre of rotation and hence are located radially inwardly and immediately adjacent the elements in the stream. The curved periphery 142 of the cover 138 acts as a cam surface, urging the elements 147 as their outer surface engages the underside of the curved periphery 142 into the groove 136.

The elements are aligned along the wall in a single substantially end-to-end line with the exception of a very few filter elements, called Ts, which align themselves substantially radially of the bowl. Since the cover 138 normally is spaced from the bottom closure a distance substantially equal to the diameter of the filter elements, it is not possible for axially aligned Ts to form adjacent the wall 128.

As shown in detail in FIG. 7, the radially aligned T's 148 are arrested by the curved periphery 142, and prevented from movement radially outwardly to the wall 128. The curved periphery 142 is shaped so as to not only act as cam surface for the elements 148 moving into the groove 136 but also as a stop to arrest radial movement of radial Ts 148. The curve is such that the limit of outward radial travel of the elements 148 is less than the radial distance of the midpoint of the groove 136 from the spindle 132 but greater than the radial distance of the inboard edge of the groove 136 from the spindle 132.

Radial TS 148 therefore project partially over the groove 136. The flow of filters in the stream 106 is pulsating due to the nature of the removal of the filters by the wheel 112, as described above, and hence the stream of filters in the groove 136 have the same pulsating motion. Filter elements 146 upon encountering the periphery 142 deflect the element 148 radially inwardly of the wall 128 and also, due to the pulsating movement of the element 146, impart a component of motion to the T so that the element 148 tends to be knocked out of radial alignment towards a tangential alignment.

Therefore, the stream of filter elements in the groove 136 does not include any radially aligned filter elements since such elements are removed by a'combination of the shape of periphery 142 and the elements in the groove 136.

While the above description of the action of the bowl 126 is with reference to rotation of the bowl 126 in a clockwise direction, the same effect is achieved if the bowl 126 is rotated in an anticlockwise direction. In this case it is necessary to reverse the position of the tube 146 so that the mouth 150 points in the direction from which the stream of filter elements is coming.

The bowl 126 must be rotated at a certain minimum speed so that the centrifugal forces can overcome the frictional and gravitational forces holding the mass of elements in their random orientation. This minimum value varies considerably over a wide range depending on a number of factors, including the weight of the elements involved and the diameter of the bowl 126. The bowl 126 may be rotated at any convenient speed corresponding to the rate of feed of filter elements required from the bowl 126, typically at a rate corresponding to a rate of feed of elements to the filter applying apparatus of about 700 per minute.

As the end-to-end aligned, generally continuous, stream of filter elements reaches the finger 149, the individual elements of the stream engaged by the finger 149 are deflected from their plane of movement into the mouth 150 of the tube146. The stream of elements thereby passes into the tube 146 and consequently is fed to the filter applying machine as stream 106. The motive power required to feed the stream through the pipes 146 and 108 is provided by the impetus of the elements of the stream in the bowl 126 and hence by the rotation of the bowl.-lf desired, suction may be applied to the tube 146 to aid the removal of the elements from the bowl.

In the case where a continuous stream of elements is formed, as the elements are removed from the bowl 126 at the tube 146, a gap forms in the rear portion of the stream. The gap is present only momentarily and more elements from the mass located in the bowl 126 instantly occupy the gap. The end-to-end aligned stream of filter elements thereby is self-perpetuating, so long as there remain filter elements in the bowl 126 able to occupy the space left by the ones removed.

It will be seen, therefore, that the feed of filter elements through the tube 146 is substantially continuous provided that a feed supply of elements is maintained in the bowl 126. The rate of feed of filter elements through the tube 146 depends on the speed of rotation of the bowl 126, provided that the filter applying machine is able to receive all of the filters fed through the tube.

If the flow of elements in the tube 146 needs to be stopped this may be done readily at the station to which the elements are fed, such as by stopping the conveyors 110. The bowl may continue to rotate and the stream becomes stationary, sliding in the groove 136, until the flow through the tube 146 recommences. Since, in continuous operation, individual filter elements 1 17 are removed in index-like manner from the front of the stream 106 the elements in the stream in the bowl are removed in pulsating or index manner.

When vacuum is applied over an arcuate length of the groove 136, this usually is applied just upstream of the point of commencement of removal of the filter elements from the bowl 126 by the action of the finger 149.

The use of the vacuum may be of assistance in maintaining the stream in the groove 136 and thereby assist in removing the filter elements from the bowl 126 as a substantially continuous stream, especially when the bowl 126 is rotated at a high speed.

The use of the finger 149 aids in removal of the filter elements by imparting thereto an upward deflection, so that the elements readily enter the mouth 150 of the tube 146. The finger may be omitted, if desired.

It is possible to use any other convenient arrangement for removing the elements from the bowl 126 as a substantially continuous stream.

Therefore, the present invention provides a means of directly feeding two-length filters to a filter applying apparatus. By the use of the present invention, it is possible to cut initially the continuous filter rod into twolength filter elements. It is not necessary to stack these elements in any regular fashion, since they may be fed as a scrambled mass to the unscrambling device 104. The filter elements therefore may be transported from the filter rod forming machine in any convenient manner to the hoppers of the filter applying machines. Further, there may be used as feed to the unscrambling device 104 two-length filter elements formed in any special manner.

Modifications are possible within the scope of the invention.

What we claim is:

1. A method of providing a feed of light weight, elongated elements which comprises establishing a cylindrical zone having an inner periphery, said zone rotating about a substantially vertical axis and being closed at its lower end, feeding a plurality of elements into said zone, subjecting said plurality of elements to centrifugal forces in said zone to form a stream of elements around said inner periphery, said stream substantially consisting of said elements in end-to-end alignment, and generating a frictional force from said centrifugal force on said stream in the direction of said alignment, leading said stream to a confined channel, and passing said stream through said channel by said centrifugal force.

2. A method of providing a substantially continuous flow of cigarette filters for use as feed to a cigarette filter applying apparatus, which comprises providing a substantially cylindrical zone having an inner periphery, said zone rotating about a substantially vertical axis and closed at its lower end, feeding a plurality of cigarette filter elements into said zone to provide at least a predetermined minimum number of said elements in said zone, rotating said zone to subject said plurality of filter elements to centrifugal forces above a minimum speed to form around asid inner periphery in a substantially horizontal plane a single stream of filter elements from said predetermined minimum and a residual mass of filter elements radially inwardly of said stream, said stream substantially consisting of filter elements in end-to-end alignment, generating frictional forces on said stream from the centrifugal forces in the direction of said stream, leading said stream in a closed channel, as a continuous flow, from said zone, and maintaining at least said predetermined minimum number of said elements in said zone, whereby upon said removal of filter elements from said stream, filter elements from said residual mass occupy the vacant portions of said inner periphery thereby self-perpetuating said stream and said residual mass is maintained.

3. The method of claim 2 wherein said continuous flow is removed from said cylindrical zone as a pulsating flow.

4. The method of claim 2 wherein any filter-elements in said stream aligned radially are removed from said stream.

5. The method of claim 2 wherein said filter elements are removed from said stream by subjecting said stream at a location around said periphery to a deflecting force to deflect said stream at an angle from said horizontal plane and out of said zone. 

1. A method of providing a feed of light weight, elongated elements which comprises establishing a cylindrical zone having an inner periphery, said zone rotating about a substantially vertical axis and being closed at its lower end, feeding a plurality of elements into said zone, subjecting said plurality of elements to centrifugal forces in said zone to form a stream of elements around said inner periphery, said stream substantially consisting of said elements in end-to-end alignment, and generating a frictional force from said centrifugal force on said stream in the direction of said alignment, leading said stream to a confined channel, and passing said stream through said chanNel by said centrifugal force.
 2. A method of providing a substantially continuous flow of cigarette filters for use as feed to a cigarette filter applying apparatus, which comprises providing a substantially cylindrical zone having an inner periphery, said zone rotating about a substantially vertical axis and closed at its lower end, feeding a plurality of cigarette filter elements into said zone to provide at least a predetermined minimum number of said elements in said zone, rotating said zone to subject said plurality of filter elements to centrifugal forces above a minimum speed to form around asid inner periphery in a substantially horizontal plane a single stream of filter elements from said predetermined minimum and a residual mass of filter elements radially inwardly of said stream, said stream substantially consisting of filter elements in end-to-end alignment, generating frictional forces on said stream from the centrifugal forces in the direction of said stream, leading said stream in a closed channel, as a continuous flow, from said zone, and maintaining at least said predetermined minimum number of said elements in said zone, whereby upon said removal of filter elements from said stream, filter elements from said residual mass occupy the vacant portions of said inner periphery thereby self-perpetuating said stream and said residual mass is maintained.
 3. The method of claim 2 wherein said continuous flow is removed from said cylindrical zone as a pulsating flow.
 4. The method of claim 2 wherein any filter elements in said stream aligned radially are removed from said stream.
 5. The method of claim 2 wherein said filter elements are removed from said stream by subjecting said stream at a location around said periphery to a deflecting force to deflect said stream at an angle from said horizontal plane and out of said zone. 